From 99b7de33477882b86d54ce8ecbf90147f9d106d7 Mon Sep 17 00:00:00 2001 From: Stas Sergeev Date: Thu, 23 Mar 2006 02:59:41 -0800 Subject: [PATCH] [PATCH] x86: early printk handling fixes The history is that -mm kernels do not work for me for a few months already. The things started from crashing somewhere after starting init, and for the last month - no boot at all, just "Uncompressing... OK, booting kernel", and silence. Early console didn't work too. With the latest releases this degraded into an infinite stream of the "Unknown interrupt or fault" messages. So today my patience ran out and I started to think how can I collect at least some info for the bug-report. Attached is the patch that allows to gather some valueable debug info on the problem by making an early console more useable. I can't properly test the patch, as the kernel still doesn't boot, so I'll explain it in details in a hope someone else can justify the intrusive changes. arch_hooks.h: added prototypes for setup_early_printk() and early_printk(). setup.c: killed wrong setup_early_printk() prototype. Moved setup_early_printk() a bit earlier, as it was not "early enough" to cover the bug I was fighting with. early_printk.c: made it to start printing from the bottom of the screen, otherwise the messages interfere with the ones of the boot-loader, so you can't read them. Signed-off-by: Stas Sergeev Cc: Andi Kleen Cc: Zwane Mwaikambo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/setup.c | 23 ++++++++++------------- arch/x86_64/kernel/early_printk.c | 3 ++- include/asm-i386/arch_hooks.h | 3 +++ 3 files changed, 15 insertions(+), 14 deletions(-) diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index 5f58f8c..2d87829 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -1459,6 +1459,16 @@ void __init setup_arch(char **cmdline_p) parse_cmdline_early(cmdline_p); +#ifdef CONFIG_EARLY_PRINTK + { + char *s = strstr(*cmdline_p, "earlyprintk="); + if (s) { + setup_early_printk(strchr(s, '=') + 1); + printk("early console enabled\n"); + } + } +#endif + max_low_pfn = setup_memory(); /* @@ -1483,19 +1493,6 @@ void __init setup_arch(char **cmdline_p) * NOTE: at this point the bootmem allocator is fully available. */ -#ifdef CONFIG_EARLY_PRINTK - { - char *s = strstr(*cmdline_p, "earlyprintk="); - if (s) { - extern void setup_early_printk(char *); - - setup_early_printk(strchr(s, '=') + 1); - printk("early console enabled\n"); - } - } -#endif - - dmi_scan_machine(); #ifdef CONFIG_X86_GENERICARCH diff --git a/arch/x86_64/kernel/early_printk.c b/arch/x86_64/kernel/early_printk.c index 6dffb49..6fcdcb8 100644 --- a/arch/x86_64/kernel/early_printk.c +++ b/arch/x86_64/kernel/early_printk.c @@ -21,7 +21,7 @@ #define MAX_XPOS max_xpos static int max_ypos = 25, max_xpos = 80; -static int current_ypos = 1, current_xpos = 0; +static int current_ypos = 25, current_xpos = 0; static void early_vga_write(struct console *con, const char *str, unsigned n) { @@ -244,6 +244,7 @@ int __init setup_early_printk(char *opt) && SCREEN_INFO.orig_video_isVGA == 1) { max_xpos = SCREEN_INFO.orig_video_cols; max_ypos = SCREEN_INFO.orig_video_lines; + current_ypos = max_ypos; early_console = &early_vga_console; } else if (!strncmp(buf, "simnow", 6)) { simnow_init(buf + 6); diff --git a/include/asm-i386/arch_hooks.h b/include/asm-i386/arch_hooks.h index 28b96a6..238cf42 100644 --- a/include/asm-i386/arch_hooks.h +++ b/include/asm-i386/arch_hooks.h @@ -24,4 +24,7 @@ extern void trap_init_hook(void); extern void time_init_hook(void); extern void mca_nmi_hook(void); +extern int setup_early_printk(char *); +extern void early_printk(const char *fmt, ...) __attribute__((format(printf,1,2))); + #endif -- 2.7.4